Method of treating canned liquids



Dec. l, 1936.

w. PAGE -:T Al. v. 2,062,331 METHOD oF TREATING CANNED LIQUID-b Filed sept; 6, 1955 2 sheets-Sheet 1 N m@ le z ill" a Q 5; I KQ 4Dec 1936 A w. PAGE 'ET AL 2,062,331

. METHOD oF TREATING CANNED LIQuIDs Filed sept. 6, 1955 2 sheets-sheet 2 INVENTORS fu rfv? @ai 507 .7210@ @ENA A ORNEYS Patented. Dsc. 1, 1936 f UNITEDSTATES aosassi g l ME'rnon or Tammo cANNEDIuQUms wana-rage, scandale, ma Burt E. nylon.

Mount 'Vernon, N. Y., assigner to The Borden Company, New York, N. Y., a corporation of- New Jersey Application september s, 1935,

Scrill No. 39,432

s cam. (ci. ss-zoi The invention relates to an improvement in' methods of treating canned liquids,` and is more particularly an improvement in sterilizing or.

pasteurizing and then cooling preserved milk 5 such as. unsweetend, evaprated or condensed milk as distinguished from sweetened,.evaporated or condensed milk, and other uids preserved inthe usual cylindrical tin cans, or cans of other shapes. The invention' is also applicable to the treatment of raw fresh milk and other fluids such as fruit juices enclosed in cans and intended for early consumption after the canning and sterilizing or pasteurizing treatment. Although the invention is applicable tothese various uses, for the sake of convenience it willl be 'described in connection with the .sterilizing of canned evaporated milk and the pasteurizing of canned raw milk, since theseh two processes are substantially identical, except in the temperatures employed and the length of time of the treatment.

Evaporated milk is 'usually enclosed in tinlined cylindrical cans before itis sterilized. The

process of sterilizing theevaporated milk mustA surfaces of the cans, with the result that there 35- is non-uniformity of taste, texturey and color. Sometimes too that portion of the milk in con tact with the inner surfaces of the metal walls of the c'ans absorbs a part of the tin coatingof the cans. A slight metallic avorlis thus imparted to 40- the milk, which is objectionable tosome people.

In view of these conditions in the usual commercial methods ofsterilizing canned evaporated milk, efforts have long been directed to agitating the cans during the sterilizing treatment in order 45. to bring all portions ofthe contents of the cans into contact successively with the inner surfaces of the cans in order that the heat treatment thereof and the resulting sterilization may be uniform so as to produce a product of uniform tex- 5 ture and color and having as nearlyaspossible .the taste of `mattu'al milk. These 'efforts have heretofore, however, not been crowned with complete success; The evaporated milktreated by the present commercial sterilizing methods can, when "55 mixedV with water-to restorethe milk to its nor# Y reduced.

m`al fluidity, still .be distinguished from raw or natural milk because of its cookedfiavor and other indications of the ing it.

One object ofthe present invention is to provide a methodof sterilizing evaporated milk and pasteurizing rawmilk enclosed in containers by -which the full'natural avor of fthe milk is vr'e-l tained and no cooked or metallic taste is imparted to the milk. In carrying out this improved meth-v od of sterilizing evaporated milk and pasteurizing raw milk, the milk enclosed in-the containers is violently agitated, as by causing it `to move rapidly centrifugaily and endwise in the containers; 'I'his combined action is eifectedby rotating the containers on their longitudinal axes and preferably simultaneously reciprocating them, thereby methodsemployed in sterilizg constantly bringing fresh portions of the milk into contact with the inner surfaces of the containers. It will be *understood in this connection that the walls of the' containers will travel at a higher rate of speed than the liquid confined I thereby, and so result in a constant shiftingv of i the milk inthe containers. Periodically the direction of 'rotation of the containers is suddenly reversed so as to secure a more intimate mixing of the contents'of the-containers and thereby l moreI efficiently successively bring` fresh portions the containers. This action is further made more eective by reciprocating the containers during thereof into contact with the inner surfaces of the' rotation thereof. lSince all portions of the milk or other liquid enclosed in the containers is constantly being brought into contact .with and then immediately afterwards moved out of 'contact with the inner surfaces of the containers, it

will be understood that higher sterilizing and pasteurizing temperatures can be employed with#- out liabilityof cooking the solid contents ofthe Y' liquid in contact with the walls'of the containers,- and also that the time heretofore required for sterilizing and pasteurizingvcan be substantially The preferredform of apparatus for practicing the improved method of sterilizing and pasteurizing milk or other uids containedl incylindrical cans is illustrated in the accompanying drawings, in which Fig. 1 is a side elevation of an apparatus adapted both fpr sterilizing canned evaporated' milk and pasteurizing canned'raw milk; Fig.` ,Y 2 is a longitudinal vertical section of theappa-` ratus shownin Fig. 1, on a slightly enlarged scale;

Fig. 3 is a transverse section taken on the line 3-3' of Flg.`2, but on an enlarged scale; and Fig.`v 4 is anv end elevation of one of the cylindrical containers held in position in the perforated drum, but with the hinged section of the drum thrown back so that the container may be placed therein for' treatment and afterwards removed therefrom.

Thesterilizing and pasteurizing apparatus il-v lustrated 'in the drawings; comprises essentially the chamber 5 and arranged to rotate and move two parts, a stationary longitudinally-arranged cylindrical shell or chamber5, and a cylindrical can-holding drum 6 located axially within axially within the chamber. The chamber is supported by the standards. 1 the upper ends of which arel semi-circular in shape in order to close-l The innerV side of the cover 9 is provided with a circular rib I2 which presses against a circular gasket I3 in the flange.

. The uid medium for treating. the contents of the cans held in theA drum `6 enters the interior o'f the chamber 5 through the holes I4 in the top si'de thereof which aline with the holes I5 inthe lower side ofa pipe I8 secured longitudinally along the vtop of the outer surface of the chamber. The sterili'zing and pasteurizing `'is preferably effected by steam which enters the pipe I6 from the valve controlled pipe I1 provided withoa gage I 8. The condensate gatheringin the bottom of the chamber 5 passes into the valve-controlled pipe I9.

.Upon the completion of the sterilizing or the pasteurizing' operation, the valve 2I in the pipe I1 is closed, and the valve 22 in the pipe 23 is'opened to permit cold water or other cooling medium to pass through the chamber .5 and out through the pipe I9 in order to bring the temperature of the contents of the cans inthe drum 6 to the desired degree. ,The chamber 5 is provided withA ing -fluid to have access directly to the outer surfaces of the series oi' cans 26 held in the drum. One end of the drum is closed by the head 21 provided with thetrunnion 29 which, is .lournalled in the boss 29-extending axially outwardly from the chamber head or cover 9 andclosed at its outer end. The other end of the drum 6 is closed by the head 3I. provided with the elongated trunnion 32 which is received within a sleeve 33 journalled in the bearing 34 secured to the head 8 of the chamber 5. Leakage between the sleeve 3 3 and bearing 34 is prevented by a gland l35 o* usual arrangement. 'I'he outer end of the trunnion 32 is secured to the sleeve 33 by means o f a bolt 31 so that rotary and reciprocatorymove-- ments mayfbe imparted to the drum 8. Thedrum is rotated' by means of al gear 38 mounted on the outer end of the shaft 3 9 supported in the uprights 4u. on the shaft as' is mounted an eien- .gated pinion 42 which engages with and drives a gear 43 fixed on the outer solid end of the sleeve 33. The gear 38' is driven by a pinion 4I actuatf ed by a reversing motor of conventional type, generallyindicated by the reference numeral 44. The reciprocatory or shaking. movements are imparted to the drunii by means of a crank construction 45, the crank rod 49 of which is provided on its outer end with a ball 41 whichis held against the recessed outer end of the solid portion of the sleeve 33 by' means of a threaded cap 48. T'he elongated pinion 42 permits Athe gear 43 to travel longitudinally under the action of the crank 45 -Whilerotating the drum6. To avoid the' compression-of air in the bearing portion 29 of the cover 9 of the chamber 5 a passageway 49leads from the closed outer end of the bearing 29 into the interior of the chamber 5.

In order that the sterilizing and pasteurizing treatment of the milk or other liquid contained in the cans 26 may be most eciently performed, it is necessary that there be no lag or lost motion between the cans and the drum 6, in other words, that the cans be positively held and' driven by the drum. To this end the inner surfaces ofthe drum at uniform intervals, depending upon .the

length of the cans under treatment, -are provided with the wedge-shaped pieces 5| which point radially 'inwardly and are arranged to press against the rims ofthe ends of the cans, as shown' in Figs. 2, 3 and 4. The wedge-shaped canholding pieces 5I are conveniently arranged in groups of three throughout the length of the apparatus which can be constructed to. hold any convenient numberof cans arranged axially in a single line, depending upon mechanical considerations and upon the diameter. of thecans. The cans are placed in the drum 6 when the latter is removed from the chamber 5 and the hinged section 52 `is swung outwardly on its hinge 53, as shown in Fig. 4. When the section 54 of the drum has been filled to capacity with cans the .section 52 thereof is closed down on the cans andthe 'two sections are held together by the springbolts 56.` It will be observed that the section 54 of the drum is provided with two wedge-shaped pieces 5I and that'the section 52 of the drum is provided with a single wedge-shaped piece 5I,1 which when the section 52 is in clo'sed position, as shown in Fig. 3, is located radially half-way between the two wedge-shaped pieces 5I' in the'dru'm section 54 which initially receive the cans (while the drum is in charged position,

as shown in Figs.4 and 3) and holdthem 'in position until the wedge-shaped piece 5I of the drum section 52 is brought down against the upper edges of the/ends of the cans to` hold them rmly 'during thereof.

the rotating and axial movements The inner end of the drum 6 is provided with two wheels 58 which. are'arrangedto travel on the tracks 59 located inthe bottom of the chamber 5 when the drum 8 is moved into and with'- drawn from the chamber 5. By reference-to Fig.

2, it will be observed'that when' the drum 6 is in operative position within the chamber 5 the wheels 58 clear the inner ends o'f the tracks 59 so as not to interfere with the rotation of the drum at anyaxial position within the chamber 5.. The boit 31 .is se arranged with relation te f -the wheels 58 that when it is in vertical position the wheels sa aline with thetreeks 5s', thereby.

paratus is easily. eiected, because when the wheels 58 are placedy on the tracks 59- n inserting the drum into the chamber 5 the holes in the trunnion 32 and the sleeve 33 come .into alinement when the drum 6 has been pushed inwardly until the' outer end of the trunnion v32 'bears against the ing treatment. For the sterilizing treatment it is assumed that the cans contain unsweetened evaporated milk. The function of the steriliza-` tion is to destroy the micro-organisms contained in the milk which in time may prove deleterious to the milk. Now these micro-organisms can be destroyed at varying temperatures held for varying lengths of time. The lower the temperature employed the -longer is the time required to'destroythe micro-organisms, and conversely, the higher the temperature employed, the shorter will be the time required for the sterilization. In the former methods of sterilizing evaporated milk it has not been feasible to use the higher temperatures, say those ranging up to 260 F. because of the liability of cooking or scorching the casein andv other solid contents of that portion of the milk in direct contact with the inner surfaces of the cans and thereby imparting a' granular rtexture andthe cooked taste to'the milk which manyl people find objectionable. .According to the present invention, on the contrary, it is feasible to employ the higher ranges of sterilizing' temperatures because no portions of the evapo rated milk are in contact with the inner surfaces of the cans long enough to permit the casein andother solids of the milk to be cooked, and consequently, the objectionable cooked taste cannot be imparted to the milk. The range of speed at which the drum 6 and the cans held thereby may be rotated varies widely, but with satisfactory sterilization results at various speeds. For example, a speed of 200 to 300 revolutions per minute gives satisfactory results in sterilizing with temperatures up to about 248 F., whereas'by employing speeds ranging up to'about 1500 revolutions per minute a sterilizing temperature of 260 F. may be used, and the time required with such speeds and vsuch temperaturesv for complete sterilization is not more than five minutes, a period considerably less than thatrequired at the present time employing sterilizingtemperatures of from about 232 F. to about 248 F. The rate of reciprocation is preferably proportionate or comparable tcr the speed of rotation, and may range from' about 25 reclprocations per minute to about 75 reciprocations per minute, and even higher.

Pasteurization of raw milk may be effected at temperatures of about 143 to 145 F., but at these' temperatures the time required is about 30 minutes. Iftemperatures of about 160 to about 165 F. are employed satisfactory pasteurization can be effected in less than a minute. By imparting the centrifugal and reclprocatory movements to the raw milk according to the principles of the present invention a higher temperaturel'than even 165 F. may be employed at a correspondingly reduced period required for effective pasteurization.

. Not only must the sterilization and pasteurizing be effected so that all portions of themilk or Aother liquid are constantly brought .momentarily intocontact with the inner surfaces of the can4 so as to avoid imparting a cooked flavor thereto and so that a uniform smooth texture and natural taste will be present in all portions of the milk,

but it` is also necessary for this latter result that the' cooling of the milk or other uid be effected n 3 under the same conditions. Accordingly, when the valve 2l is closed in the steam pipe I1, and

the valve 22 is opened in the cold'water pipe 2l,

the drum ii continues to rotate, first in one direction and then in the opposite direction, the reverse direction of rotation being periodic, and the reciprocatory motion is still imparted to the drum and the cans held thereby while the -cold water cools the contents' of the cans down tothe required degree, so that the cooling is effected 1mi-v formly throu hout the contents of the cans.

By sterilizi g andcooling canned evaporated milk in practising the present invention. a p'roduct results which has a smooth uniform texture free from granules of cooked solid ingredients of the .milk and a taste or flavor closely approachl ing that of natural milk. Raw canned milk pasteurized according to thepresent invention is almost' if not entirely free-from the cooked flavor now commonly noticed in pasteurized milk. `By

violently agitating the evaporated milk during the sterilization thereof, it is not necessary to shake the cans on the completion of the sterilizing treatment, which-is the usual practice in the pres--` ent commercial sterilizing methods.

Having thus described the invention, what we claim as new isz- 1. The method of treating liquids enclosed in l t containers held against movement in directions transverse to the axes of the containers, whichcon'sists in rotating the containers ontheir axes to impart a centrifugal and rotary movement to',

their contents within the containers while sub jecting the containers externally to heating and cooling media successively.

2. The method of treating liquids enclosed in containers held against movement in directions transverse to the axes of the containers, which consists in rotating the .containers on their longitudinal axes to impart a centrifugal and rotary ers, periodically reversing the direction of rotamovement to their contents within the containf tion of the containers, reciprocating the contain- ,ers 'during their rotation, and subjecting the containers externally to heating and media successively. H

3. The method of treating liquids enclosed in cylindrical containersiheld against movement in directions transverse to the axes of the contain ers, which consists in rotating'the containers on axes of the cans, which'consists in imparting to the liquid a centrifugal, rotary and reciprocacooling tory movement within the cans so as lto constantly bring different portions of the liquid into contact with the inner surfaces lof the cans, and applying4 sterilizing and cooling media successively tov the outer surfaces ofthe cans.

5. The method of successively sterllizing or pasteurizing and cooling milk contained in cylindrical cans held against movement in directions transverse to the axes of the containers,- which `consists in imparting to the milk a cen- `trifugal and' lrotary movement in one direction for 'a predetermined period of time, and periodi..

cally reversing the. direction of the centrifugal ,w

and rotary -movement oi the milk, while succes 'sively applying sterilizing or pasteurizing and cooling media to the outer surfaces of the cans.

6. The method of sterilizing evaporated milk contained in a cylindrical can held against movement in directions transverse to the axis of the can which consists in rapidly rotating the can on its longitudinal axis in one direction to impart a centrifugal and rotary movement to the l V10 milk within the can, periodically reversing the;

can externally, and then cooling the can and its contents. Y

WALTER PAGE. BURT E. TAYLOR. 

